textproduct: Rapid City

KEY MESSAGES

- Hot through the weekend with elevated to near critical fire weather conditions.

- Isolated strong storms this afternoon/evening. A marginal risk (1 out of 5) of severe storms Sunday afternoon/evening.

- Slightly cooler conditions finally look to return next week.

DISCUSSION

(This Evening Through Saturday) Issued at 1254 PM MDT Sat Jul 18 2026

Upper ridging continues the western CONUS, with several upper waves approaching the region from the west/southwest. Surface obs show temps have been lagging in the 70s and 80s, but are now rising quickly since the low clouds dissipated. Dewpoints are still well into the 60s across western SD within deep southeasterly flow. Have dropped max temps today to the low to mid 90s across most locations. Still looking at some afternoon and evening storms today. SBCAPE of ~1200 J/kg is expected within the corridor from SCentral SD through the Black Hills into parts of NE WY/NW SD. The next wave is approaching from NCentral and will cross NE WY/NW SD this evening. Shear is strongest across NW SD, where southeasterly low level winds are strongest. Storms are expected to initiate across the Black Hills this afternoon...then NE WY/SE MT in the late afternoon/early evening. As storms track into NW SD just north of the Black Hills, could see a storm or two with gusty winds/hail. These storms will continue eastward toward a less favorable environment over NCentral SD, where both instability and shear weaken. The thermal ridge over the central/northern Rockies will slide eastward overnight tonight toward the CWA, bringing back very hot temperatures. Highs on Sunday will be in the triple digits. Dewpoints will be more reasonable (50s) but will still result in advisory threshold heat index. Will not make any changes to heat-related headlines. A cold front will cross MT and push into ND late Sunday, which will result in strong/severe storms over those areas. By the time the front gets to NW SD, it seems to stall before resurging southward early Monday morning. Still unclear with the severe weather threat Sunday afternoon. It appears the bulk of severe storms will be north and east of the CWA. Good instability and somewhat decent shear will be present, but the forcing with the frontal boundary might be missing. Regardless, could still see convection develop from transient outflow boundaries or orographically from the Black Hills and Bighorns. Any storms that develop may be severe, but think better organization will be limited to areas east of the CWA where increased forcing/shear will be present. Cooler Canadian high pressure will build across the northern Plains for the first half of the week. Uncertain about max temps Monday behind the cold front, which does seem to struggle pushing out the very warm H85 temps. Could still be a hot day on Monday, but wouldn't be surprised if it ends up being a tad cooler than what the NBM shows. Better cold air advection is expected Monday night into Tuesday should bring lower temps...but we'll likely still see highs in the upper 80s to lower 90s. Better chances for precip are expected for the second half of next week.

AVIATION

(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 515 PM MDT Sat Jul 18 2026

Isolated thunderstorms have developed over the Black Hills/northeast WY late this afternoon. The overall motion of these storms will be to the east. That being said, these storms should fade out quickly once they track far enough away from the mountains. Gusty, erratic winds and brief heavy rain will occur with any storm along with local IFR conditions.

Outside of those storms, mainly VFR conditions are expected through the TAF period.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory until 9 PM MDT /10 PM CDT/ Sunday for SDZ001-002- 012>014-025>027-030>032-041>044-046-047-049-072>078. WY...Heat Advisory until 9 PM MDT Sunday for WYZ054>056-058>060.